This notebook covers the period June-September 1886. All of the entries are by Edison. The name of John F. Ott appears frequently as a witness. The book contains notes, drawings, and calculations relating to lamp experiments. The lamps are numbered I through 18 and 159 through 222. Loose pages containing the results of lamp tests have been pasted onto many of the notebook pages. The spine is labeled "35." The pages are unnumbered, and the book has been used in both directions. Approximately 200 pages have been used. Some pages have been torn out of the book. Courtesy of Thomas Edison National Historical Park.